Sucrose phosphate synthetase isolated from maize

ABSTRACT

A protein having sucrose phosphate synthetase (SPS) activity is isolated from plants, preferably maize. The protein has a molecular weight of 110-130 dK and contains at least one peptide selected from Thv Trp Ile Lys, Try Val Val Glu Leu Ala Arg, Ser Met Pro Pro Ile Trp Ala Glu Val Met Arg, Leu Arg Pro Asp Gln Asp Try Leu Met His Ile Ser His Arg and Trp Ser His Asp Gly Ala Arg. Isolation is carried out by obtaining an extract from the plant by grinding, centrifugation and filtration; enriching the extract in SPS protein by precipitation in an appropriate solvent such as polyethylene glycol, centrifugation and solubilization of the precipitate obtained in a buffer solution; subjecting the protein thus obtained to low pressure anion exchange chromatography, chromatography on heparin Sepharose and high pressure anion exchange chromatography; and purifying the active fractions obtained by passage through two high pressure chromatography columns. Hybridomas and monoclonal antibodies are prepared from an antigen resulting from high pressure anion exchange chromatography above, antibodies directed specifically against SPS are selected and the antibodies are used to purify the SPS obtained previously. Complementary DNA coding for the SPS is prepared and used to modify expression of the SPS in plant cells.

PRIOR APPLICATION

The application is a continuation of U.S. patent application Ser. No. 07/842,337, filed Jul. 22, 1992, now abandoned.

Sucrose phosphate synthetase (SPS), its preparation process, its complementary DNA and the use of the complementary DNA to modify the expression of the SPS in vegetable cells.

The present invention relates to saccharose phosphate synthetase (SPS), its preparation process, its complementary DNA and the use of the latter to modify the rate of expression of SPS in vegetable cells.

A subject of the invention is proteins having the activity of saccharose phosphate synthetase (SPS).

By vegetable cell is meant all plant cells being able to form undifferentiated tissue such as calluses or differentiated tissues such as embryos, certain parts of plants, whole plants or also seeds.

By plant is meant notably plants producing seeds, for example the grasses such as straw cereals such as wheat, barley, maize or oats, the legumes such as soya, oleaginous plants such as sunflowers, plants with tubers such as potatoes, plants with roots such as beetroots or fruits such as tomatoes.

More particularly a subject of the invention is saccharose phosphate synthetase and notably the saccharose phosphate synthetase of plants.

By plants is meant for example the grasses such as for example wheat, barley, maize, sugar cane, vegetables such as tomatoes and soya, fruits, such as apples and bananas.

Saccharose phosphate synthetase is a key enzyme in the regulation mechanisms of saccharose, but also in the regulation mechanisms of the distribution of carbon between starch and saccharose in photosynthesis (see on this subject the article by Jack PREISS in TIBS January 1984, pages 24 and following, or also the article by Mark STITT and Coll. in Biochemistry of Plants vol. 10, 1987 pages 327 and following).

The SPS appears to be specific to the species concerned; Joan L.-Walker and Steven C. Huber who have purified and carried out a preliminary characterization of the saccharose phosphate of spinach indicate clearly that the antibodies obtained recognize exclusively the SPS of spinach (cf PLANT PHYSIOL (1989) 89, 518-524).

More precisely a subject of the invention is the SPS of maize.

The SPS of maize can exist in a pure or practically pure form.

More precisely a subject of the invention is the proteins defined previously of molecular weight of the order of 110 to 130 kD appearing in the monomer, dimer or tetramer form and their derivatives having at least one peptide whose amino acid sequence is the following:

ThrTrpIleLys (SEQ ID NO.: 1)

TyrValValGluLeuAlaArg (SEQ ID NO.: 2)

SerMetProProIleTrpAlaGluValMetArg (SEQ ID NO.: 3)

LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg (SEQ ID NO.: 4)

TrpSerHisAspGlyAlaArg (SEQ ID NO.: 5)

Notably a subject of the invention is the proteins defined previously having the amino acid sequence described in FIG. 7. (SEQ ID NO.: 11)

Also a subject of the invention is the derivatives of the proteins defined previously modified by genetic engineering techniques and presenting the activity of the SPS.

Also a subject of the invention is a preparation process characterized in that:

a) an extract is made from parts of the plants preserved at low temperature by grinding, centrifugation and filtration,

b) the extract obtained is enriched in SPS protein by precipitation in an appropriate solvent, centrifugation and solubilisation of the precipitate obtained in a buffer solution,

c) the active protein thus obtained is purified by chromatography and if desired,

d) the hybridomas and monoclonal antibodies are prepared from an antigen solution obtained from one of the preparations obtained in paragraphs a), b), and c) above,

e) the hybridomas are screened and the monoclonal antibody or antibodies directed specifically against the SPS are selected,

f) the SPS obtained is purified by means of the antibodies prepared in this way.

More precisely a subject of the invention is a process characterized in that:

a) an extract is made from parts of maize plants preserved at low temperature by grinding, centrifugation and filtration,

b) the extract obtained is enriched in proteins by precipitation in polyethyleneglycol, centrifugation and solubilisation of the precipitate obtained in a buffer solution,

c) the SPS protein thus obtained is purified by low pressure anion exchange chromatography, then by chromatography on heparin Sepharose, then by high pressure anion exchange chromatography,

d) the active fractions are purified by passage through 2 high pressure chromatography columns, and, if desired,

e) the hybridomas and monoclonal antibodies are prepared from an antigen solution obtained from a preparation a), b), c),

f) the hybridomas are screened and the antibodies directed specifically against the SPS are selected,

g) the SPS obtained previously is purified by means of antibodies thus prepared.

In a preferred embodiment:

the maize used is a maize of PIONEER 3184 strain,

the parts of maize plants used are leaves preserved at low temperature for example between -50° C. and -90° C.,

the purification in polyethyleneglycol (PEG) takes place in two stages:

a first precipitation where the final concentration of PEG is close to 6%,

a second precipitation where the final concentration of PEG is close to 12%.

the various chromatographies are carried out as follows:

1st chromatography: DEAE Sepharose,

2nd chromatography: heparin Sepharose: it should be noted that the preparation thus obtained can be preserved for several days without major loss of activity,

3rd HPLC chromatography: Mono Q chromatography,

4th HPLC chromatography: hydroxylapatite,

5th HPLC chromatography: DEAE.

in the course of these various purification stages and the following, the measurement of the SPS activity is preferably carried out using two different methods:

a) a method based on a colorimetric test or a resorcinal test,

b) a method based on the determination of one of the products formed during the transformation reactions involving the SPS. These two methods are detailed in the experimental part set out hereafter.

mice are immunized with several injections of the purified enzymatic preparation.

Different mouse types can be used, for example BALB/C mice.

The antigen is used in the complete Freund adjuvant then in the incomplete Freund adjuvant.

Several injections of the antigen are administered to the mice: good results were obtained with three injections of mono Q fractions followed by three injections of final fractions (on days 0, 14, 27, 60, 90 and 105 for example).

The first injections are carried out by subcutaneous route, for example in the foot pads, the last injection is carried out by intravenous route in the tail for example.

the preparation of cellular suspensions of spleen thus immunized is treated in a clonic fashion.

The stages of fusion with myeloma cells, preservation of the hybridomas, cloning and production of the antibodies are achieved according to known methods.

To detect the hybridomas secreting the antibodies directed against the antigen, two methods are used to select the detection antibodies of the secreting hybridomas directed against the immunization antigen:

a method of detection of antibody inhibitors of SPS activity,

a method of antibody activity directed against SPS activity.

These methods are preferably those described in the experimental part.

Also a subject of the invention is the cell lines of the hybridomas obtained and notably the cell lines of the following hybridomas:

SPA 2-2-3: I-971

SPA 2-2-22: I-970

SPA 2-2-25: I-972

SPB 3-2-19: I-973

SPB 5-2-10: I-974

SPB 5-4-2: I-975

SPB 13-1-7: I-976

SPB 13-2-2: I-977

which were deposited on 11th Jun. 1990 with the Collection Nationale de Culture de Microorganismes (CNCM-Institute Pasteur) under the numbers mentioned.

Also a subject of the invention is monoclonal antibodies directed specifically against the SPS.

Also a subject of the invention is a preparation process for proteins characterized in that a preparation containing said proteins is passed through a chromatography column containing the monoclonal antibodies directed specifically against said proteins and in this way the desired proteins are obtained. Also a subject of the invention is the DNA coding sequences for the proteins defined previously and notably the SPS of maize, whose sequence appears in FIG. 7.

The complementary DNA (cDNA) coding for the saccharose Phosphate Synthethase (SPS) enzyme was prepared as follows:

1--Sequencing of purified SPS peptide fragments.

Purified preparations of maize SPS obtained previously give, upon separation on acrylamide gel, a minor band of 120 kd (corresponding to the total protein sequence) and two major bands of 90 and 30 kd. These two polypeptides are separated by electrophoresis then electroelution. Trypsic digestion followed by the sequencing of fragments obtained allowed the amino acid sequences of 5 peptides to be determined (FIG. 3). Knowledge of the amino acid sequence of these peptides allows the corresponding nucleotide sequence to be determined.

2--Isolation of the RNA of maize leaves.

The total RNA is isolated according to the TURPEN and GRIFFITH method (1986, Biotechniques vol.4 pp 11-15).

The RNA polyA+ is prepared by passage through a column of oligodT cellulose according to known techniques.

3--Construction of a cDNA library.

The cDNA synthesis is carried out using the "PROMEGA"® synthesis kit. The reverse transcriptase of MMLV is used in place of AMV reverse transcriptase. The size of cDNA's obtained is comprised between 500 base pairs and several thousand base pairs. ECoRI adapters are added to the ends of the cDNA before cloning in a lambda gt11 expression vector. The cDNA library contains approximately 1.5×10⁶ transformants.

4--The use of PCR for the synthesis of a specific nucleotide probe for SPS.

The oligonucleotides derivatised from B11 peptide sequences (coming from 30 kd) and 4K (coming from 90 kd) described in FIG. 3 are used as initiators in PCR-type reactions. The starting hypothesis is that the polypeptides of 30 and 90 kd are the degradation products of the SPS protein of 120 kd. Therefore the peptides resulting from the SPS 30 and SPS 90 fragments have to come from the translation of the same RNA messenger. In this hypothesis the use of a pair of oligonucleotides corresponding to the peptide sequences in a PCR-type reaction has to result in the synthesis of a DNA fragment of determined size if these oligonucleotides are complementary to an indentical DNA sequence. Not knowing the respective position peptides in the SPS protein, the various combinations are tried out. Only the pair of CD3 oligonucleotides (FIG. 4) gives a DNA fragment of determined size (1200 base pairs).

5--Screening the cDNA library:

250,000 lambda gt11 transformants have been screened using the DNA fragment of 1200 base pairs obtained by PCR reaction (described previously). 16 positive clones have been obtained. The insertion sizes vary from 0.3 kb to 2.8 kb. The sequence obtained is not complete on the R' side. A second screening of the library using a DNA fragment of 400 bp corresponding to the 5' part of the SPS3 clone allows a clone (SPS 61) to be obtained which goes further in the 5' part (FIG. 6) without having the 5' terminus.

6--Production and screening of a second cDNA library allowing the cloning of the 5' part of the cDNA coding for the SPS.

An oligonucleotide complementary to the 5' sequence of the SPS61 clone is used as initiator for the synthesis of the cDNA. After synthesis of the second strand, the cDNA was cloned in the lambda phage. The library contains approximately 1 million clones. The SPS 90 and SPS 77 clones were obtained during the screening of this library with SPS 61 (FIG. 6). The sequence of these clones has allowed the region overlapping with the SPS 61 clone to be determined. The SPS 90 clone allows the 5' part of the SPS to be reached.

Verification of the organization of the different sequences (FIG. 6) allowing the complete cDNA sequence to be obtained was able to be carried out by using the PCR technique. The initiators used belong to the SPS 3 and SPS 90 clones. The obtaining of a fragment of 750 base pairs of the exact size predicted by the complete sequence permits the assertion that the SPS 3 and SPS 90 clones derive from the same RNA messenger.

7--Assembly of the complete cDNA.

Also a subject of the invention is the genomic DNA containing the coding part for the proteins defined previously and sequences necessary for the expression and regulation of this protein in plants.

Also a subject of the invention is a process for modifying the expression rate of the SPS in a plant, characterized in that the cells of said plant are transformed by means of an expression vector containing the cDNA defined previously.

Also a subject of the invention is a vector allowing the expression of the SPS protein under the control of a promoter capable of directing the expression and preferably the superexpression of said SPS in a plant cell and a 3' region containing transcription regulation signals for the expression of the gene coding for the SPS.

Moreover a subject of the invention is the plants obtained by the implementation of this process.

Also a subject of the invention is the seeds obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the SDS-PAGE profile illustrating the purification of maize saccharose phosphate synthetase.

FIG. 2 is an autoradiograph of maize saccharose phosphate synthetase showing strong signals at protein bands 120 kd, 95 kd and 35 kd.

FIG. 3 shows the sequences of 5 peptides with molecular weights of 90 kd and 30 kd from the SPS protein.

FIG. 4 shows the sequence of peptides called CD3 and

FIG. 5A shows the PCR reaction of CD3 and CD4.

FIG. 5B is an autoradiograph of CD7 and CD4 reactions.

FIG. 6 is a restriction map of cDNA coding for SPS.

FIG. 7 is the protein sequence deduced from study of the open reading phase of cDNA coding for SDS.

FIG. 8 shows the electrophoresis band of peptides anti SPS 90 and anti SPS 30 rabbit sera.

FIG. 9A is a gel of total proteins isolated from a 30 day old maize plant and

FIG. 9B shows the western analysis of using a mixture of anti SPS 30 and anti SPS 90.

The following examples illustrate the invention without however limiting

1--PURIFICATION OF SACCHAROSE PHOSPHATE SYNTHETASE OF MAIZE

1.1--Determination method of the enzymatic activity (SPS)

The monitoring of the SPS activity during purification is carried out in 2 ways:

a) either by means of a calorimetric test (P. S. Kerr et al., Planta 1987, 170: 515-519) so-called resorcinol test.

The saccharose Phosphate Synthetase or UDP glucose--D Fructose--Phosphate Glucosyltransferase catalyses the reaction:

    UDPG-Fructose 6-P=Saccharose 6-P+UDP

UDPG: Uridine Di-Phospho Glucose

Fructose 6-P or F6P: Fructose 6-Phosphate

Saccharose 6-P: Saccharose 6-Phosphate

The saccharose 6-P formed reacts with the resorcinol to give a red-coloured compound quantifiable by spectrophotometry at 520 nm (D.O. 520 nm).

b) or by means of a paired enzymatic system (S. Harbron and al., Anal. Biochem. 1980, 107: 56-59) made up in the following manner:

    UDPG+F6P<=>SACCHAROSE 6P+UDP

SPS

    UDP+ATP<=>ADP+UTP

Nucleoside D phosphokinase NP₂ K

    ADP+PEP<=>Pyruvate+ATP

Pyruvate kinase PK

    pyruvate+NADH<=>NAD+lactate

Lactate dehydrogenase LDH

The disappearance of NADH at 340 nm is measured and 1 mol of NAD formed or 1 mol of NADH consumed corresponds to 1 mol of saccharose 6 P formed.

1.2--Purification of the SPS (preparation of the immunogen)

1.2.1--Extraction

The starting material for the purification is constituted by young maize leaves (Pioneer 3184 strain) cut up, de-veined, deep-frozen in liquid nitrogen and stored at -70° C.

250 g of leaves are suspended in 1 liter of HEPES buffer 50 mM MgCl₂ 10 mM EDTA 1 mM DTT 5 mM pH 7.5 (extraction buffer) with 11 g Polyvinylpyrrolidone added, with nitrogen bubbled through it and cooling to 0° C.

The leaves are ground until a homogeneous suspension is obtained. This suspension is filtered. The resultant product is then centrifuged at 14000 g for 20 mn at 4° C.

While maintaining the bubbling through of nitrogen, a solution of 50% Poly Ethylene Glycol (PEG 8000 "Breox" 50% p/v in extraction buffer) is added to the supernatant until a final PEG concentration of 6% is reached. After centrifugation, 20 mn at 14000 g, 50% PEG is added to the supernatant until a final PEG concentration of 12% is reached. After centrifuging again, the supernatant is eliminated and the pellet is solubilised with 60 ml of HEPES buffer 50 mM, MgCl₂ 10 mM, EDTA 1 mM, DTT 5 mM, Ethylene Glycol (EG) 10%, KCl 0.08M pH 7.5 (resuspension buffer). This solution is clarified by centrifuging 10 mn at 40000 g. The supernatant constitutes the final extract.

1.2.2--Low pressure anion exchange chromatography:

DEAE Sepharose fast-flow exchanger

The final extract is chromatographed on a column of DEAE Sepharose Fast-Flow equilibrated in a resuspension buffer. After washing the column with the same buffer, the proteins adsorbed on the support are eluted by means of an increasing ionic strength of linear gradient between 0.08M KCl and 0.35M KCl in the HEPES buffer 50 mM, MgCl₂ 10 mM, EDTA 1 mM, DTT 5 mM, EG 10% pH 7.5 (buffer A). The flow rate applied during this experiment is 180 ml/h and chromatography is carried out at 4° C.

The SPS activity is eluted at approximately 0.17M KCl.

1.2.3--Chromatography on Heparin Sepharose

The fractions containing the SPS activity are combined and diluted to 1/5th in buffer A then added to 12 ml Heparin Sepharose previously equilibrated in buffer A. After incubation for one hour with slow agitation at 4° C., the gel is washed with approximately 10 volumes of buffer A+0.05M KCl then reconditioned in a chromatographic column.

The adsorbed proteins are eluted in an isocratic manner by means of a CAPS buffer 10 mM, MgCl₂ 10 mM, EDTA 1 mM, DTT 5 mM, EG 10%, Tween 80 0.01%, Heparin 1 mg/ml, Fructose 1%, KCl 0,25M pH 10 delivered at 60 ml/h. Chromatography is carried out at 4° C.

The fractions containing the SPS activity are combined (heparin fraction) and preserved on ice until the following purification stage. The enzyme at this stage is stable for at least a week.

The following purification stages are carried out using a High Performance Liquid Chromatography system (HPLC), and purification is monitored by means of a detector equipped with a filter allowing the ultra-violet absorption at 280 nm (A280) to be measured. The buffers and recovered fractions are maintained at low temperature.

1.2.4--High performance anion exchange chromatography: Mono Q

The heparin fraction is diluted to 2/3 in Triethanolamine buffer 20 mM, MgCl₂ 10 mM, EDTA 1 mM, DTT 10 mM, EG 3%, Tween 80 0.3% pH 7.5 (buffer A) and loaded onto an HPLC Mono Q HR10/10 column previously equilibrated with the same buffer with NaCl added (final concentration 0.18M). After returning to 0 the proteins of the A280 adsorbed on the chromatographic support are eluted by means of a salt complex gradient made up as follows:

buffer A: cf above

buffer B: buffer A+NaCl 1M

    ______________________________________                                                time (minutes)                                                                          % B                                                            ______________________________________                                                0        18                                                                    0.1      24                                                                    15       24                                                                    19       26                                                                    23       26                                                                    33       31                                                                    38       31                                                                    41       100                                                                   43       18                                                             ______________________________________                                    

The flow rate applied on the column is 180 ml/h.

The SPS activity is eluted between 0.26 and 0.31M NaCl. The active fractions are brought together (Mono Q fraction).

1.2.5--HPLC on Hydroxyapatite

The Mono Q FRACTION is loaded on an HPLC column of hydroxyapatite equilibrated with the buffer KH2PO4/K2HPO4 20 mM, EG 3%, Tween 80 0.3%, DTT 5 mM pH 7.5. After return to 0 the adsorbed proteins of the A280 are eluted by means of the following phosphate gradient:

buffer A: cf above

buffer B: idem buffer A but with 500 mM of K phosphate

    ______________________________________                                                time (minutes)                                                                          % B                                                            ______________________________________                                                0        2                                                                     5        11                                                                    9        13                                                                    14       13                                                                    29       40                                                                    31       100                                                                   32       100                                                                   35       2                                                              ______________________________________                                    

The flow rate applied is 60 ml/h. It should be noted that at this stage the phosphate is a partial inhibitor of the SPS activity and it is therefore difficult to calculate a specific activity as well as a purification factor (cf table 1).

The SPS activity is eluted in these conditions with about 60 mM phosphate.

The active fractions are combined and constitute the HAC fraction.

1.2.6--HPLC on DEAE 5PW

The HAC fraction is loaded on a Di Ethyl Amino Ethyl (DEAE-5PW) type of anion exchange HPLC column previously equilibrated in a Triethanolamine buffer 20 mM, MgCl₂ 10 mM, EDTA 1 mM, EG 3%, DTT 2.5 mM, Betaine 2% pH 7.5 (Buffer A)+0.15M NaCl.

After return to 0 the adsorbed proteins of the A280 are eluted by means of the following NaCl gradient:

buffer A: cf above

buffer B: idem buffer A with 1M NaCl

    ______________________________________                                                time (minutes)                                                                          % B                                                            ______________________________________                                                0        15                                                                    0.1      20                                                                    5        20                                                                    22       35                                                                    27       35                                                                    30       100                                                                   31       15                                                             ______________________________________                                    

The flow rate used is 60 ml/h.

The SPS activity is eluted with approximately 0.3M NaCl.

1.2.7--Obtaining the final preparation: concentration

The final preparation is concentrated by HPLC chromatography on Mono Q HR5/5 exchanger (5×50 mm, Pharmacia) and rapid elution.

The DEAE 5PW fraction (or the G200 fraction) is diluted to 2/3 in buffer A (idem 6) and loaded on the column which has been previously equilibrated with buffer A+0.18M NaCl. The following gradient is then applied on the column:

buffers A & B: (idem 6)

    ______________________________________                                                time (minutes)                                                                          % B                                                            ______________________________________                                                0        18                                                                    10       40                                                                    12       100                                                                   13       18                                                             ______________________________________                                    

The flow rate used is 60 ml/h.

The SPS activity is eluted with approximately 30% B (0.3M NaCl).

The final preparation is stored at -20° C. until use.

Table 1 summarizes the results obtained at the different stages of purification in terms of the quantities of proteins and SPS activity.

                  TABLE 1                                                          ______________________________________                                                  Protein                                                                        concentration                                                                            Volume   Sa**        Y*                                              (mg/ml)   (ml)     (U)    Pf** (%)                                    ______________________________________                                         Homogenate 1           1000     0.05 0    100                                  Final extract                                                                             4 < <8      60       0.30 6    144                                  DEAE FF frac.                                                                             0.4< <0.8   70       3    60   168                                  Heparin frac.                                                                             0.2 < <0.4  25       9    180  90                                   Mono Q frac.                                                                              (0.02)      30       --   --   --                                   HAC frac.  (0.03)      8        --   --   --                                   Final prep.                                                                               0.05        2        25   500  5                                    ______________________________________                                          Key                                                                            Sa = Specific enzymatic activity: 1 U corresponds to 1 micromole of            saccharose formed per minute per mg of protein at 37° C.                Pf = Purification factor                                                       Y = Yield                                                                      () = approximate value                                                         -- = not determined                                                            Remarks: ** the measurement of the quantity of proteins is carried out by      using the Bradford method. The Tween interferes greatly in this method, i      is not possible to determine the proteins and therefore to calculate an S      at the level of stages containing it. In addition the phosphate being an       inhibitor of the SPS activity, the determination during the HAC stage          gives an underestimated result.                                                * the increasing output during the first stages may be explained by the        elimination during purification of some 5 inhibitors of the SPS activity.

A profile (SDS-PAGE) illustrating the purification process and the quality of the final preparation is given in FIG. 1. The presence of 120, 95, and 35 Kd (Kilodaltons) proteins is correlated with the SPS activity.

Sequence studies of 35 and 95 Kd proteins carried out subsequently, seem to show that these proteins are probably degradation products of the 120 Kd protein. In addition, the antibodies directed against the 35 and 95 Kd proteins also recognize the 120 kd protein by immuno-detection after transfer onto a membrane, which demonstrates an antigen community between these three proteins (see further on). It must be pointed out, however, that adding protease inhibitors to the buffers during purification did not allow a 120 Kd protein to be obtained solely.

The saccharose phosphate synthetase seems therefore to be a di- or tetrameric protein having a 120 Kd protein (homo-dimer or homo-tetramer) as a base sub-unit.

Key to FIG. 1

The SDS-PAGE profile illustrating the purification of the maize saccharose phosphate synthetase: acrylamide gel at 8.5%, reducing conditions and staining with silver nitrate M: Standard molecular weight B-Galactosidase (116 Kd), Bovine albumin (68 Kd), Ovalbumin (45 Kd), Carbonic anhydrase (29 Kd).

H: Heparin Fraction, 30 micrograms of proteins per well.

FP: Final Preparation, 7.5 micrograms of proteins per well.

FE: Final Extract, 7.5 micrograms of proteins per well.

D: DEAE Fast-Flow Fraction, 7.5 micrograms of proteins per well.

The protein bands which are visible at about 120 Kd (1), 95 Kd (2) and 35 Kd (3) are correlated, in the course of the chromatography stages, to the presence of an SPS activity in the fractions.

2--PREPARATION PROCESS FOR THE MONOCLONAL ANTIBODIES DIRECTED AGAINST THE SACCHAROSE PHOSPHATE SYNTHETASE

2.1--Immunizations

BALB/C mice are immunized by sub-cutaneous injection (pads and paws) according to the following methodology:

Day 0 Injection of approximately 5 micrograms of proteins (i.e. approximately 0.3 USPS per mouse): Mono Q pool emulsified volume for volume with Freund's Complete Adjuvant (FCA).

Day 14 Injection of approximately 5 micrograms of proteins (i.e. approximately 0.3 USPS per mouse: Mono Q pool emulsified volume for volume with Freund's Incomplete Adjuvant (FIA).

Day 27 Idem D14

Day 0+2 months Injection of approximately 20 micrograms of proteins: final preparation in FIA

Day 0+3 months Injection of approximately 12 micrograms of proteins: final preparation in FIA

Day 0+4.5 months Injection by intravenous route (IV) in the tail of approximately 20 micrograms of proteins: final pool as is.

Fusion is carried out 3 days after the IV immunization. Serums are taken on D34, D67, D98 and D159 in order to measure the immune response (cf screening).

2.1.1--Screening method

As the SPS used for the immunizations is not perfectly homogeneous, it is necessary to perfect a specific screening test for this enzyme. In fact an ELISA-type test also reveals antibodies directed against SPS non-related impurities which are present in the preparations having served as immunizations.

Two antibody detection methods are used:

detection method for antibody inhibitors of the SPS activity

detection method for antibodies directed against the SPS (inhibitors or not).

a) Detection method for antibody inhibitors of the SPS activity

This screening method allows antibodies binding at the level of the SPS active site or at the level of a site close to it, to be detected and therefore preventing substrate access. In practice 70 μl of serum or supernatant of the hybridoma culture diluted in an appropriate manner is added to 70 μl of SPS preparation (Heparin fraction). After incubation for one hour at ambient temperature, the residual activity is determined using coupled enzymatic determination (Cf I-1). Results are expressed as a percentage of inhibition compared to the same SPS preparation treated in the same manner without antibodies.

b) Detection method for antibodies directed against the SPS (inhibitors or not)

This method is based on the precipitation of an antibody-SPS complex using a trainer system (mouse Ig anti-Ig coupled with Sepharose balls: Goat-anti mouse-Sepharose or GAM Sepharose). In practice 60 microliters of serum or supernatant of hybridoma culture diluted in an appropriate manner is added to 60 microliters of SPS preparation (Heparin fraction). After incubation for 2 hours at ambient temperature, the mixture is added to 50 microliters of GAM-SEPHAROSE at 25% washed 3 times beforehand with a HEPES buffer 50 mM, MgCl₂ 10 mM, EDTA 1 mM, EG 10%, DTT 5 mM pH 7.5. The mixture is incubated overnight at 4° C. under vibrational agitation. After centrifuging for 5 minutes at 3000 rpm the residual SPS activity in the supernatant is determined using coupled enzymatic determination (cf 1.1). The results are expressed as a precipitation percentage (% prec.) compared to the same SPS preparation treated in the same manner without antibodies.

2.1.2--Results

10 mice were immunized according to the protocol described above. The following table gives the results of precipitation determinations carried out with the heteroantisera of 10 mice on D159. The serums are diluted to 1/200.

    ______________________________________                                         MOUSE   1     2      3   4    5   6    7   8    9   10                         % PREC. 45    22     32  64   36  30   22  16   39  37                         ______________________________________                                    

Additional dilutions of the serum of mouse 4 gives the following results:

    ______________________________________                                         DILUTION     % PRECIPITATION                                                   ______________________________________                                         1/200        67                                                                1/400        48                                                                1/600        29                                                                1/1000       20                                                                ______________________________________                                    

The spleens of mice 1 and 4 are used for the fusion.

0 2.2--Cellular fusion

Mouse splenocytes are fused with SP2/0-Ag-14 mouse myeloma cells in a ratio of 2/1 in the presence of polyethylene glycol 1500 at 45%. The selection of the hybridomas is carried out by adding hypoxanthine and azaserine to the culture medium 24 and 48 hours after fusion.

The hybridomas are cloned and subcloned by the method of dilution limits.

2.2.1--Results of screening of the hybrids and clones

    ______________________________________                                         HYBRIDS                                                                        MOUSE 4 (SPA fusion)                                                                              MOUSE 1 (SPB fusion)                                        ______________________________________                                         2 positive Hybrids in 45                                                                          6 positive Hybrids in 52                                    SPA2: 38% prec.    SPB3: 17% prec.                                             SPA19: 7% prec.    SPB5: 67% prec.                                                                SPB8: 53% prec.                                                                SPB13: 68% prec.                                                               SPB25: 13% prec.                                                               SPB34: 17% prec.                                            ______________________________________                                         CLONES                                                                         FUSION SPA         FUSION SPB                                                  ______________________________________                                         2 clones retained in 36                                                                           7 clones retained in 46                                     SPA2-2: 85% prec.  SPB3-2: 19% prec.                                           SPA19-7: 8% prec.  SPBS-1: 76% prec.                                                              SPB5-2: 71% prec.                                                              SPB5-3: 45% prec.                                                              SPB5-4: 24% prec.                                                              SPB13-1: 79% prec.                                                             SPB13-2: 53% prec.                                          ______________________________________                                         SUBCLONES                                                                      SPA FUSION         SPB FUSION                                                  ______________________________________                                         3 subclones retained in 48                                                                        5 su;bclones retained in 72                                 SPA2-2-3: 60% prec.                                                                               SPB3-2-19: 21% prec.                                        SPA2-2-22: 33% prec.                                                                              SPBS-2-10: 86% prec.                                        SPA2-2-25: 92% prec.                                                                              SPB5-4-2: 46% prec.                                                            SPB13-1-7: 87% prec.                                                           SPB13-2-2:93% prec.                                         ______________________________________                                    

2.2.2--Production of anti-SPS monoclonal antibodies

The hybridomas are injected by intraperitoneal route to BALB/c female mice treated beforehand with pristane. The monoclonal antibodies are partially purified from ascitic liquids thus produced by precipitation with 18% sodium sulphate. The precipitated proteins are dissolved then dialyzed against the PBS (F18).

2.2.3--Characterization of anti-SPS monoclonal antibodies

a) type

The type is determined using an ELISA test. Antibodies of rabbit anti-IgG and mouse anti-IgM (ZYMED) are fixed at the bottom of wells on 96-well plates. After one night at ambient temperature the non-occupied sites are saturated with a solution of bovine serum albumin at 3% in PBS. After one hour of incubation at 37° C. and several washings, the different F18's are deposited in the wells. After incubation and several washings, the goat or rabbit antibodies, anti-class and anti-subclass of mouse immunoglobulins, coupled with peroxidase, are added. After one hour at 37° C., the antibodies are revealed using the H₂ O₂ /ABTS system.

All the anti-SPS monoclonal antibodies are of Ig G₁ type.

b) Inhibition of the SPS activity

Determination of the capacity of the antibodies to inhibit the SPS activity is carried out using the technique mentioned above (cf 2.1.1 a) using the F18's.

    ______________________________________                                                  Concentration of antibodies                                                    (micrograms/ml)                                                                               % Inhibition                                           ______________________________________                                         Antibodies                                                                     SPA2-2-3   50               0                                                  SPA2-2-22  50               0                                                  SPA2-2-25  50               0                                                  SPB3-2-19  50               0                                                  SPB5-2-10  50               0                                                  SPB5-4-2   50               0                                                  SPB13-1-7  50               50                                                            25               55                                                            5                25                                                            2.5              10                                                            1                2.1                                                SPB13-2-2  50               60.1                                                          25               59.1                                                          5                33.8                                                          2.5              14.2                                                          1                8.7                                                ______________________________________                                    

c) Immuno-precipitation of the SPS activity

Determination of the capacity of the antibodies to immuno-precipitate the SPS activity is carried out using the technique mentioned above (cf 2.1.1 b) using the F18's.

    ______________________________________                                                Concentration of antibodies                                                    (micrograms/ml)  % Precipitation                                        ______________________________________                                         Antibodies                                                                     SPA2-2-3  50                95                                                           25                92                                                           5                 80                                                           2.5               40                                                           1                 20                                                 SPA2-2-22 50                95.7                                                         25                95                                                           10                51                                                           5                 48.2                                                         2.5               25                                                           1                 10                                                 Antibody                                                                       SPA2-2-25 50                91.3                                                         25                95.3                                                         5                 90.4                                                         2.5               22.8                                                         1                 12.5                                               SPB3-2-1 9                                                                               50                95                                                           25                95                                                           5                 27.8                                                         2.5               17.8                                                         1                 9.3                                                SPB5-2-10 50                95                                                           25                95                                                           5                 81.1                                                         2.5               41.4                                                         1                 22.6                                               SPB5-4-2  50                95                                                           25                95                                                           5                 86.1                                                         2.5               57.2                                                         1                 26.1                                               SPB13-1-7 50                95                                                           25                95                                                           10                65.4                                                         5                 48.1                                                         2.5               15                                                           1                 10                                                 SPB13-2-2 50                95                                                           25                95                                                           5                 71.8                                                         2.5               43.5                                               ______________________________________                                    

3--USE OF MONOCLONAL ANTIBODIES FOR THE CHARACTERISATION AND PURIFICATION OF SACCHAROSE PHOSPHATE SYNTHETASE

3.1--Characterization of Maize Saccharose Phosphate Synthetase

This characterization is carried out using SPB3-2-19 and SPB13-2-2 antibodies by the technique of immuno-detection after transfer of the proteins from an electrophoresis gel under denaturing conditions (SDS PAGE) on to a nitro-cellulose membrane. After migration in acrylamide gel at 12.5% (Nature 227 (1970) 680-685), the proteins are transferred onto a 0.22 μm nitro-cellulose gel (Schleicher and Schuell) by means of a transfer vat for 30 mn, the initial current being 1 Ampere. The buffer used is the standard electrophoresis buffer (TRIS base 3.03 g/l, Glycine 14.4 g/l, SDS 0.1% pH 8.3) to which 20% methanol is added. After transfer, the membrane is put in a saturation bath (Casein 0.5% in PBS) in order to saturate the sites non-occupied with proteins originating from the gel. After 1 h at 37° C. under gentle agitation, the membrane is washed 3 to 4 times with a washing buffer (Casein 0.1%, Tween 20 0.5%, in PBS) then incubated with a solution of 10 micrograms/ml of the monoclonal antibodies to be tested. A part of the membrane is incubated in parallel with a non-immune antibody (negative control). After incubation for 1 hour at ambient temperature followed by 9 to 10 washings, the membrane is incubated in the presence of a mouse anti-antibody antibody labelled with Iodine 125 diluted in washing buffer (50000 cpm per cm² of membrane). After incubation for 1 hour at ambient temperature followed by 9 to 10 washings, the membrane is dried then autoradiographed (film X-OMAT AR KODAK and filter amplifier Cronex XTRA Life DUPONT). An autoradiograph is shown in FIG. 2. A strong signal is observed at the level of the protein bands 120 Kd, 95 Kd and 35 Kd which correlates with the previous results (see first section).

Key to FIG. 2

A: membrane incubated in the presence of the SPB3-2-19 antibody

B: membrane incubated in the presence of an antibody not directed against the SPS (anti-neomycin monoclonal antibody negative Control)

C: membrane incubated in the presence of the SPB13-2-2 antibody M: molecular weight markers radiolabelled with I125 (NEX-188 NEN) B-Galactosidase (116 Kd), Bovine albumin (68 Kd), carbonic anhydrase (29 Kd), Trypsic inhibitor (20.1 Kd), Alpha-Lactalbumin (14.4 Kd), 150000 cpm per deposit

PA: deposit of proteins obtained after immunoaffinity chromatography (see below) with the monoclonal antibody SPB13-2-2, approximately 40 micrograms of proteins per deposit.

H: deposit of Heparin fraction, approximately 40 micrograms of proteins per deposit.

3.2--Purification of the Saccharose Phosphate Synthetase by immunoaffinity

A methodology for purification of the maize Saccharose Phosphate Synthetase on an immunoaffinity support was developed in order to increase the quantity of protein recovered by reducing the number of purification stages and to thus allow sequencing studies.

3.2.1--Preparation of the immuno-adsorbant

The F18 (see 2.2.2) corresponding to the SPB13-1-7 antibody or to the SPB13-2-2 antibody is added to activated CH-Sepharose, at the rate of 1 mg of antibody per ml of gel. After incubation for 2 h at ambient temperature, the sites not occupied by antibodies are saturated with 1M ethanolamine pH 9. The support is then washed alternately with an acetate buffer 0.1M NaCl0.5M pH 4 and a TRIS buffer 0.1M NaCl0.5M pH 8. The immunoaffinity support thus prepared is preserved at 4° C. in HEPES buffer 50 mM, MgCl₂ 10 mM, EDTA 1 mM, PMSF 1 mM, Sodium nitride (azide) 0.01% pH 7.5.

3.2.2--Immunoaffinity chromatography

The Heparin fraction corresponding to the purification of the SPS has 50% PEG added to it (see 1.2.1) until a final concentration of 20% PEG is reached. After incubation for 30 mn at 4° C. with slow agitation, the mixture is centrifuged at 1600 g for 30 mn. The protein pellet is taken up in half the volume of starting buffer 50 mM HEPES, 10 mM MgCl₂, 1 mM EDTA, 10% ethylene glycol pH 7.5. This stage allows the elimination of the previous buffer which is incompatible with immunoaffinity chromatography and concentration of the proteins. The yield of SPS activity is 80 to 90%.

The solution obtained is applied at a flow rate of 0.1 ml/mn on to 1 ml of immunoaffinity support packed into a column and on which has been fixed an antibody not directed against the SPS (activated CNBr-SEPHAROSE, on which is fixed an anti-neomycin antibody). This first stage allows some contaminants which fix themselves in an aspecific manner on the chromatography support to be eliminated. The non-specific column effluent is in its turn applied on the anti-SPS immunoaffinity support (2 ml in a 11×20 mm column) with a flow rate of 0.1 ml/mn. These two stages are carried out at laboratory temperature. After washing the column with 10 ml of loading buffer then with a washing buffer (loading buffer with NaCl 0.25M and Tween 20 0.3% added to it) until the absorption in the ultraviolet at 280 nm is close to the base level, the proteins adsorbed on the support are eluted with a solution of triethylamine 50 mM pH 11. This elution is carried out at 4° C. and the immunoaffinity column is turned upside down to obtain an optimum yield. The SDS PAGE profile of the final preparation obtained corresponds to what is obtained with a standard protocol (see 1). It should be noted that the elution method for proteins adsorbed on the immunoaffinity support is non-reversibly inhibitory to the SPS activity but the recovery yield of SPS-linked proteins is optimal by comparison with tests carried out in conditions of native elution. The immunoaffinity column eluant is desalted using the G25 column, against a buffer of 0.14% Glycerol, 0.07% B-mercaptoethanol, 0.04% SDS, 0.9 mM TRIS pH 6.8 (electrophoresis buffer in reducing conditions diluted 70 times). After desalting, the protein preparation is concentrated 70 times using a vacuum concentrator and the SPS proteins are purified by SDS-PAGE (see below).

EXAMPLE 1

Construction of a complete cDNA coding for the SPS

A) Sequence of the SPS polypeptides

Samples of a purified protein preparation obtained as described previously are subjected to an electrophoresis in SDS acrylamide gel.

After electrophoresis, the bands of proteins are detected by treatment with potassium chloride as described by Bergman and Joernvall (Eur. Jour. Biochem. (1978) 169, 9-12) and the bands observed corresponding to molecular weights of 90 kD and 30 kD are excised. The proteins are electro-eluted from these gel fragments using an Electrophoretic Concentrator according to the manufacturer's recommendations (ISCO; Lincoln, Nebraska) in 4 mM of sodium acetate, pH 8. After electro-elution, the quantities of proteins recovered are determined by comparison with a solution of known concentration of bovine serum albumin (BSA) by staining with Coomassie Blue. Approximately 30 micrograms of 30 kD proteins and 75 micrograms of 90 kD proteins are obtained.

The proteins are concentrated by acetonic precipitation and put in suspension in a buffer of 50 mM of ammonium carbonate, pH 8. Tryptic digestion and HPLC purification are carried out as described by Sturm and Chrispeels (Jour. Biol. Chem. (1987) 262, 13392-13403). Briefly, the digestion is carried out by the addition of trypsin, and incubation for two hours at 37° C. The digestion is then repeated. The proteins are concentrated by lyophilization and suspended in a buffer of 50 mM of sodium phosphate, pH 2.2. This mixture is subjected to reversed phase HPLC chromatography by application on a C18 column. Elution is carried out using an increasing gradient of acetonitrile. The elution carried out with the buffer mixture of phosphate/acetonitrile gradient is monitored spectrophotometrically at 214 nm. The fractions corresponding to the absorption peaks at 214 nm are collected, lyophilized, suspended in 0.1% trifluoroacetic acid, applied again to the C18 column, and eluted using an acetonitrile gradient. The elution carried out with the trifluoroacetic acid/acetontrile gradient is monitored spectrophotometrically at 214 nm. The fractions corresponding to absorption peaks at 214 nm are collected, lyophilized, and subjected to a protein degradation of Edman type using an automatic protein sequencer (Applied Bio-systems; Foster City, Calif.). Sequences of 5 peptides are obtained. (See FIG. 3).

B) Isolation of RNA from maize leaves

Whole and fully developed leaves are picked from hybrid 3184 vegetative plants of Pioneer maize of two feet in height (60.96 cm). The leaves are picked late in the morning, deepfrozen in a bath of liquid nitrogen, and kept at -70° C. The total RNA is isolated according to the method of Turpen and Griffith (Biotechniques (1986) 4, 11-15). Briefly, 250 g of material is homogenized in 4M of guanidine thiocyanate and 2% sarcosyl. The mixture is then centrifuged and the supernatant called clear Lysat is deposited on a bed of 5.7M CsCl and centrifuged for 5.5 hours at 50,000 rpm. The RNA pellet is dissolved in water, extracted with phenol and chloroform, and precipitated with ethanol. The resultant pellet is suspended in water. The final yield of the isolation of RNA is quantified by UV spectrophotometry. A saturated suspension of cellulose powder/water is added to the RNA/water mixture, at 10% of the total volume, to remove the residual polysaccharides. After centrifuging, the supernatant containing the RNA is applied to a column of oligo (dT)-cellulose as described in Maniatis et al. (Molecular Cloning, A Laboratory Manual, (1982) Cold Spring Harbor, N.Y.). The fraction containing the poly (A) RNA is then applied again to the column. The eluted fraction containing the poly (A) RNA is extracted with phenol and the RNA is precipitated with ethanol.

C) Construction and screening of a cDNA library

The synthesis of cDNA is carried out according to the recommendations of the manufacturer (Systeme de Synthese RiboClone™ cDNA by Promega, Madison, Wis.), using five micrograms of poly (A) RNA as matrix, the M-MLV reverse transcriptase (BRL; Bethesda, Md.) is substituted for AMV reverse transcriptase. The EcoRI adapter oligonucleotides are added to the cDNA with free ends and the resultant fragments are cloned in an expression vector (LambdaZAP, Stratagene; La Jolla, Calif.) according to the manufacturer's recommendations. The library obtained contains approximately 1.5×10⁶ transformants.

By using the information given by the sequence of peptides of Stage A and the polymerase chain reaction (PCR), a fragment of 1200 bp corresponding to the cDNA of the SPS is generated. The total cDNA obtained from maize leaf RNA is used as a matrix and the degenerated oligonucieotides, synthesized from the data of the sequences of 30 kD and 90 kD protein peptides, are used as initiator. These initiator series are called CD3 and CD4. (FIG. 4). The use of the correct series of initiators, which is CD3, results in a fragment created by PCR reaction. The PCR reaction using the other series of initiators, CD4, does not result in the synthesis of a fragment. FIG. 5. The PCR reaction is carried out according to the manufacturer's recommendations (GeneAmp™ DNA Amplification Reagent Kit and DNA Thermal Cycler of Perkin Elmer Cetus; Norwalk, Conn.) except for the reaction which is continued for 30 cycles, and the rehybridization stages which are carried out at 50° C. for one minute. Southern analysis confirms that the PCR band is not an artefact, as shown in FIG. 5. The 4K5 probe is used because the sequence corresponding to this probe is supposed to be in the 1200 bp fragment if this fragment corresponds to the SPS sequence. The probe hybridizes at the 1200 bp band generated by PCR using the CD3 initiator series but not with the PCR products generated using the CD4 initiator series. (FIG. 5).

The 1200 bp fragment generated by PCR is labelled with ³² P ³² P=radioactive phosphorus! (following the Random Primed DNA Labelling Kit, Boehringer Mannheim, Indianapolis, Ind.) and used as a probe to screen approximately 250,000 plates of a cDNA library. Insertions of positive clones are analyzed by restriction analysis with EcoRI, and the clones possessing the longest insertions SPS#3 and SPS#18, are chosen for a more thorough analysis. (FIG. 6). A HindIII/EcoRI 400 bp fragment of the 5' terminal part of the SPS 3 is isolated, then labelled with ³² P by random labelling (Random Primed DNA Labelling Kit) and used as a probe to rescreen the library. A new clone, called SPS#61, which extends much further upstream than the SPS#3, is isolated. (FIG. 6).

To isolate the cDNA clones which contain more 5' region than the SPS#3 or the SPS#61, a new cDNA library is prepared (following the RiboClone™ cDNA Synthesis System by Promega; Madison, Wis.) using M-MLV reverse transcriptase instead of AMV reverse transcriptase. However, instead of using the oligo (dT) as initiator, a synthetic initiator, 23B, synthesized from the 5' region of the SPS#61 clone, is used. This results in the obtaining of cDNA which contains only the regions upstream of the 5' region of the SPS#61. The library is screened using the EcoRI fragment of SPS#61 labelled with ³² P as a probe, and 16 plates are positive with hybridization. The clones with the longest insertions, SPS#77 and SPS#90, are chosen for a more thorough analysis. The study of the DNA sequence of SPS#77 and SPS#90 shows that the overlapping region (of a size greater than 100 bp) with SPS#61 is identical, and that both extend further upstream in region 5'. (FIG. 6).

The PCR carried out using a single strand cDNA (obtained by reverse transcriptase reaction on the mRNA using an oligo (dT) to bring about the necessary bicatenary initiation for reverse transcriptase) as a matrix and initiators chosen from the SPS#90 and SPS#3 sequences, confirm that SPS#90 and SPS#3 come from the transcription of the same mRNA. The fragment resulting. from this PCR reaction is 750 bp in length, compatible with the size expected from study of the DNA sequence. This fragment of 750 bp is sub-cloned in a vector derived from Bluescript in the form of a SALI/HinIII fragment. Four of the resultant sub-clones were partially sequenced and the sequence obtained is identical to the sequence of the previously determined DNA.

D) Assembly of the sequence coding for the SPS

The two strands of #90, #61, and #3 are sequenced by the method of Sanger and al. (PNAS (1977) 74; 5463-5467). The reading phase of the SPS determined by knowledge of the peptide sequences, shows that the first methionine codons are placed in positions 112 bp and 250 bp. FIG. 7. The codon in position 112 bp corresponds to a eukaryotic consensus sequence for commencement of translation (Kozak, Cell (1986) 44: 283-292) and is placed 54 bp downstream of a TAG stop codon (58 bp). A translational stop is found in the SPS#3 clone, in position 1603 bp. However, another cDNA clone, obtained during the initial screening of the cDNA library (see Example 2), called SPS#18, does not have a stop codon in position 1603. Due to this fact the 1603 bp region of SPS#18 is used to bring about the final construction of complete length (see below).

The complete sequence coding for the SPS can be prepared by combining the 529 bp fragment BamHI/HindIII of the SPS#90, the 705 bp fragment HindIII of the SPS#61, the 686 bp fragment HindIII of the SPS#18, and the 1476 bp fragment HindIII/EcoRI of the SPS#3.

The five peptide sequences derived from SPS 30 kD- and SPS 90 kD- (see Stage A) are found in the protein sequence deduced from study of the open reading phase of the cDNA. (FIG. 7).

EXAMPLE 2

Detection of SPS Polypeptides by Specific Antisera

Samples of purified protein preparations obtained by the method described previously are subjected to electrophoresis in SDS acrylamide gel. The proteins of the acrylamide gel are fixed and revealed by staining. The bands corresponding to the 90 kD and 30 kD polypeptides are excised, ground up and injected into rabbits. Western analysis (as described by Oberfelder, Focus (1989) 11 (1): 1-5) shows that the antibodies isolated from the serum of the rabbit injected with the SPS 30 peptide recognize the bands corresponding to the SPS 30 and SPS 120 peptides in the SDS acrylamide gel. The antibodies isolated from the serum of the rabbit injected with the SPS 90 peptide recognize the bands corresponding to the SPS 90 and SPS 120 polypeptides. (FIG. 8).

Immunological localization of SPS in the maize plant

The total proteins are extracted from leaves of a 30-day old maize plant, picked at 11 o'clock in the morning, and they are taken to boiling point in an SDS buffer. The protein extracts are deposited on SDS acrylamide gels, in two stages. One gel is stained with Coomassie Blue, while the other is subjected to Western analysis, using a mixture of anti SPS30 and anti SPS90 antisera as a probe. (FIG. 9). The most dense bands appearing on the gel stained with Coomassie Blue are identified as being phosphoenolpyruvate carboxylase (PEPCASE), an enzyme involved in photosynthesis. The Western blot reveals the presence of the SPS. The appearance profile of SPS proteins is very similar to the appearance profile of PEPcase proteins; not present in the roots, and not present in leaf section closest to the stem, nor in the very young leaves. This profile corresponds to the expression of proteins associated with photosynthesis, and is the expected graphical representation for the SPS.

EXAMPLE 3

Construction of expression vectors

Construction of a reading system of complete length SPS

An SPS#90 clone (FIG. 6), is digested with HindIII and linked to the 705 bp HindIII fragment of the SPS#61 clone to create a plasmid containing the terminal 5' region of the coding part for the SPS. The resultant plasmid is digested with BamHI and partially digested with HindIII, resulting in a 1340 bp fragment of BamHI/HindIII containing the terminal 5' region of the SPS. The terminal 3' region of the coding part for the SPS is obtained by replacing the 686 bp HindIII fragment (positions 1340-2036) of the SPS#3 clone with the 646 bp HindIII fragment of the SPS#18 (to remove the stop codon). All of the terminal 3' region is then recovered by EcoRI digestion and partial HindIII digestion, resulting in a 1172 bp HindIII/EcoRI fragment. This HindIII/EcoRI fragment, carrying the terminal 3' region, is linked to the BamHI/EcoRI fragment carrying the terminal 5' region in a vector derived from pUC digested by BamHi/EcoRI, to create a fragment carrying all of the region coding for the SPS, that being 3406 bp.

Construction of the Small Sub-Unit Promoter Cassette of ribulose-1,5-bisphosphate carboxylase of tobacco *2!

The region coding for the SPS can be cloned in a convenient manner in the form of a BamHI/EcoRI fragment (106 pb-3506 bp) in a small sub-unit promoter cassette of tobacco (SSU).

An SSU promoter cassette, for the expression of the SPS, can be prepared as follows. The SSU promoter region comes from the PCGN627 (described below) in the form of an Asp718/SalI fragment, and linked to a plasmid pCGN1431 digested by Asp718/SalI (described below), resulting in a cassette containing the SSU promoter and the tml 3' region separated by a DNA fragment carrying the restriction sites.

After ligation of the DNA fragment coding for the SPS in the SSU/tml3' promoter cassette, the SSU/SPS/tml3' region can be linked in a binary vector and integrated in a plant genome by transformation via Agrobacterium tumefaciens. *3! pCGN627

The 3.4 kb EcoRI fragment of the TSSU3-8 (O'Neal et al., Nucleic Acids Res (1987) 15; 8661-8677), containing the promoter region of the small sub-unit of ribulose 1,5-bisphosphate carboxylase, is cloned in the EcoRI site of the M13mp18 (Yanisch-Perron et al., Gene (1985) 53: 103-119) to produce a M13 8B clone. The single strand DNA of this M13 8B phage is used as a matrix to prolong the initiation of oligonucleotide "Probe 1" whose structure is defined in O'Neal's article (O'Neal et al., Nucleic Acids Research (1987) 15; 8661-8677) by using the Klenow fragment of the DNA polymerase I. The products of this reaction with polymerase are treated with mung bean nuclease (Mung Bean Nuclease) and then digested with HindIII to produce a 1450 bp fragment containing the SSU promoter region. This fragment is cloned in pUC18 digested by HindIII-SmaI (Yanisch-Perron et al., Gene (1985) 53: 103-119) to produce pCGN625.

pCGN625 is digested by the restriction enzyme HindIII, the terminal regions are filled with the Klenow fragment of the DNA polymerase I and the plasmid thus obtained is redigested with the restriction enzyme EcoRI. The filled EcoRI/HindIII fragment containing the SSU promoter region is linked by ligation to the plasmid pUC18 digested by SmaI/EcoRI to produce pCGN627.

pCGN1431 contains the double promoter CAMV 35S and the tml 3' region with a multiple cloning site between them. This promoter/terminator cassette is contained in a vector derived from pUC which contains a chloramphenicol resistance gene instead of the ampicillin resistance gene. The cassette is flanked with multiple restriction sites for easy use.

A) Construction of pCGN986

pCGN986 contains the 35S promoter of the cauliflower mosaic virus (CaMV35) and a tml-3' region of the T-DNA with multiple restriction sites between them. The plasmid pCGN986 is derived from another cassette, pCGN206, containing the promoter of CaMV35S and a different 3' region, the VI terminal 3' region of the CaMV region. The promoter of CaMV35S is cloned in the form of an AluI fragment (7144-7734 bp) (Gardner et al., Nucl. Acids Res. (1981) 9: 2871-2888) in a HincII site of M13mp7 (Messing et al., Nucl. Acids Res (1981) 9: 309-321) to create C614. The digestion by the restriction enzyme EcoRI of C614 produces the EcoRI fragment containing the 35S promoter which is cloned in a restriction site of pUC8 (Vieira and Messing, Gene (1982) 19: 259-268) to produce pCGN147.

pCGN148a containing a promoter region, a label allowing a selection (Kanamycin with 2 ATG'S), and a 3' region, is prepared by digestion of the plasmid pCGN528 with BglII and insertion of the promoter fragment BamHi-BglII of the pCGN147. This fragment is cloned in the BglII site of the pCGN528 seeing to it that the the BglII site is close to the Kanamycin gene of the pCGN528.

The shuttle vector used for this construction of pCGN528 is achieved as follows: pCGN535 is obtained by digestion of a plasmid containing Tn5, (which carries a Kanamycin resistance gene) (Jorgensen et al., Mol. Gen. Genet. (1979) 177: 65), with HindIII-BamHI and by insertion of the HindIII-BamHI fragment containing the Kanamycin resistance gene in the HindIII-BamHI sites of the pACYC184 tetracylcin resistance gene (Chang and Cohen, J. Bacteriol. (1978) 134: 1141-1156). pCGN526 is obtained by inserting the BamHI 19 fragment of pTiA6 (Thomashow et al., Cell (1980) 19: 729-739) modified with XhoI adapters at the level of the SmaI site, in the BamHI site of pCGN525. pCGN528 is obtained by removing the small Xho fragment followed by a new ligation.

The plasmid pCGN149a is obtained by cloning the BamHI fragment of the pMB9KanXXI carrying the Kanamycin resistance gene in the BamHI site of the pCGN148a. pMB9KanXXI is a vector derived from the pUC4K plasmid (Vieira and Messing, Gene (1982) 19: 259-268) which has no XhoI restriction site but which contains the Kanamycin resistance gene of Tn903 allowing an efficient selection in Agrobacterium. *4!

pCGN149a is digested with HindIII and BamHI and linked with pUC8 (Vieira and Messing, supra) digested with HindIII and BamHI to produce pCGN169. This eliminates the Kanamycin label of Tn903. pCGN565 and pCGN169 are both digested with HindIII and PstI and religated to form pCGN203, a plasmid containing the CaMV 35S promoter and a part of the terminal 5' region of the Kanamycin Tn5 gene (up to site PstI) (Jorgensen et al., Mol. Gen. Genet. (1979) 177: 65). A 3' regulatory region is added to the pCGN203 from the pCGN204 plasmid (a EcoRI fragment of CaMV (408-6105 bp) containing the VI terminal 3' region cloned in pUC18 (Gardner et al., Nucl. Acids Res. (1981) 9: 2871-2888) by digestion with HindIII and PstI and ligation. The resultant cassette, pCGN206, is the base plasmid for the construction of the pCGN986.

The tml 3' sequences of pTiA6 T-DNA are sub-cloned from the BamHI19 fragment of the T-DNA (Thomashow et al., Cell (1980) 19 : 729-739) in the form of a BamHI-EcoRI fragment (nucleotides 9062 to 12823, following the numbering of Barker (Barker et al., Plant Mo. Biol. (1983) 2: 335-350). This sequence is combined with the pACYC184 replication origin (EcoRI-HindII fragment) (Chang and Cohen, J. Bacteriol. (1978) 134: 1141-1156) and a marker of gentamycin resistance of the pLB41 plasmid, (BamHI-HindII fragment) (D. Figurski) to produce pCGN417.

The single SmaI site of pCGN417 (nucleotide 11207 of the BamHI19 fragment) is changed into an SacI site by using adapters and the BamHI-SacI fragment is sub-cloned in pCGN565 to give pCGN971. The BamHI site of pCGN971 is changed into an EcoRI site by using adapters to produce pCGN971E. The EcoRI-SacI fragment of the pCGN971E plasmid, containing the tml 3' regulatory region, is joined to the pCGN206 plasmid after digestion by EcoRI and SacI to give pCGN975. The small part of the Tn5 Kanamycin resistance gene is removed from the terminal 3' region of the CaMV 35S promoter by digestion with SalI and BglII, by making the ends free and adding SalI adapters. The final expression cassette pCGN986 contains the CaMV 35s promoter followed by two SalI sites, an XbaI, BamHI, SmaI, KpnI site and the tml 3' region (nucleotides 11207-9023 of the T-DNA).

B) Construction of pCGN164

The AluI fragment of the CaMV (7144-7735 bp) (Gardner et al., Nucl. Acids Res. (1981) 19: 2871-2888) is obtained by digestion with AluI and cloning in the HincII site of M13mp7 (Vieira and Messing, Gene (1982) 19: 259-268) to create C614. Digestion of C614 by the restriction enzyme EcoRI produces the EcoRI fragment containing the 35S promoter. This fragment is cloned in the EcoRI site of pUC8 (Vieira and Messing, supra) to produce pCGN146. In order to decrease slightly the promoter region, the BglII site (7670 bp) is treated with BglII and Bal31 and subsequently a BglII adapter is attached to the DNA treated by Bal31 to produce pCGN147. pCGN147 is digested with EcoRI/HphI and the resultant EcoRI-HphI fragment containing the 35S promoter is transferred into an M13mp8 vector digested by EcoRI and SmaI (Vieira and Messing, supra) to create pCGN164.

C) Construction of pCGN638

The digestion of CaMV10 (Gardner, et al., Nucl. Acids Res. (1981) 9: 2871-2888) with BglII produces a BglII fragment containing a 35S promoter region (6493-7670 bp) which is linked to the BamHI site of pUC19 (Norrander et al., Gene (1983) 26: 101-106) to create pCGN638.

D) Construction of pCGN2113

pCGN164 is digested with EcoRV and BamHI to free the EcoRV-BamHI fragment containing a part of the 35S promoter (7340-7433 bp). The pCGN638 plasmid is digested with HindIII and EcoRV to free a HindIII-EcoRV fragment containing a different part of the 35S promoter (6493-7340 bp). These two fragments are linked in pCGN986 previously digested with HindIII and BamHI to remove the HindIII-BamHI fragment of the 35S promoter; this ligation produces pCGN639, which contains the skeleton of the plasmid and the tml-3' region of the pCGN986 and the two fragments of the 35S promoter of pCGN164 and pCGN638. pCGN638 is digested with EcoRV and DdeI to free a fragment of the 35S promoter (7070-7340 bp). The fragment is treated with the Klenow fragment of the DNA polymerase I to create free terminal regions and is linked to the EcoRV site of pCGN639 to produce pCGN2113 which has the fragment in a good orientation. The pCGN2113 plasmid was deposited at the ATCC (American Type Culture Collection) on 22nd Mar. 1989, Accession Number 40587.

E) Construction of pCGN1761

pCGN2113 is digested by the EcoRI restriction enzyme and the plasmid is linked in the presence of a synthetic adapter containing an XbaI site and a BamHI site (the adapter contained the cohesive EcoRI terminii of each side, but the adjacent bases are such that an EcoRI site is not reconstructed at this site) to produce pCGN2113M. pCGN2113M is digested completely by SacI and then subjected to a partial digestion by BamHI. This DNA is then treated with the T4 DNA polymerase to create free terminii and an EcoRI adapter is linked in the plasmid to the free terminii. After transformation a clone carrying a plasmid having an EcoRI site between the promoter and the intact tml-3' region is chosen and designated pCGN1761.

F) Construction of pCGN1431

The SalI-EcoRI fragment of pCGN2113, which contains the complete promoter/multiple restriction site--tml 3' cassette is recovered by SalI-EcoRI digestion and cloned in the plasmid pCGN565 digested by SalI-EcoRI to create pCGN2120. The pCGN565 plasmid is a cloning vector based on a pUC8-Cm vector carrying the chloramphenicol resistance gene (K. Buckley, Ph.D. Thesis, UC San Diego 1985), but containing the multi-restriction site of pUC18 (Yanisch-Perron et al., Gene (1985) 53: 103-119). pCGN2120 is digested totally with PstI and then linked again. A clone having eliminated only the PstI-PstI fragment of 858 bp (9207-10065, Barker et al., 1983 supra) of the tml 3' region is called pCGN1431.

Keys to FIGS. 3-9B

FIG. 3: peptide sequences derived from of the SPS protein. All the peptides are oriented N→C terminal.

FIG. 4: structure of the oligonucleotides used for the CD3 and CD4 PCR reactions in connection with the peptides (anti-direction sequences are presented in bold). The arrows indicate the direction towards which the oligonucleotides will initiate the catalysis reaction by polymerase.

FIG. 5A: electrophoresis using agarose gel of the CD3 and CD4 PCR reactions. Dimensions are given in kb.

FIG. 5B: shows an autoradiograph of the Southern blot of the CD3 and CD4 reactions read using the 4K5 oligonucleotide probe.

FIG. 6: restriction map of the cDNA coding for the SPS. The upper part represents the restriction map of the total DNA fragment coding for the SPS. The lower parts represent the structure of the different clones having been allowed by combination to achieve this restriction map. The initiation and termination translation codons are indicated.

FIG. 7: sequence of the cDNA coding for the SPS. The sequences of the SPS 90, PSP 61 and SPS 3 clones are fused at the points indicated on FIG. 4. The three reading phases have been translated. Only the open reading phase corresponding to the SPS is indicated under the nucleotide sequence. All the peptide sequences obtained during the purification and sequencing of the SPS (peptides of FIG. 3) are indicated in the sequence.

FIG. 8: characterization by the Western technique of the anti-SPS 90 and anti-SPS 30 rabbit sera. pAS**=non-immune serum, rabbit SPS 30; AS**=immunized serum, SPS 30; pAS=non-immune serum, rabbit SPS 90; AS*=anti SPS 90 immunized serum. Molecular weight markers to the left, S=SPS 120 kd polypeptide; S*=SPS 90 kd polypeptide; S**=SPS 30 kd polypeptide.

FIG. 9A: gel of total proteins isolated from a 30-day old maize plant, stained with Coomassie Blue. M=size marker; R=roots; 1-8=number of leaves counting from the base of the plant. Leaf 5 was cut into 5 segments starting from the end of the leaf (5a) up to the end of the sheath (5e). PEP=phosphoenolpyruvate carboxylase.

FIG. 9B: shows the results of a Western analysis using a mixture of anti-SPS 30 and anti-SPS 90 sera directed against the total proteins isolated from a 30-day old maize plant. The signal corresponding to the SPS appears at the 120-140 kd level.

    __________________________________________________________________________     SEQUENCE LISTING                                                               (1) GENERAL INFORMATION:                                                       (iii) NUMBER OF SEQUENCES: 37                                                  (2) INFORMATION FOR SEQ ID NO:1:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4                                                                  (B) TYPE: Amino Acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 1:                                        ThrTrpIleLys                                                                   (2) INFORMATION FOR SEQ ID NO: 2:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7                                                                  (B) TYPE: Amino Acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 2:                                        TyrValValGluLeuAlaArg                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO: 3:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 11                                                                 (B) TYPE: Amino Acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 3:                                        SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 4:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14                                                                 (B) TYPE: Amino acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 4:                                        LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 5:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7                                                                  (B) TYPE: Amino acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 5:                                        TrpSerHisAspGlyAlaArg                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO: 6:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 12                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 6:                                        ACGTGGATCAAG12                                                                 ThrTrpIleLys                                                                   1                                                                              (2) INFORMATION FOR SEQ ID NO: 7:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 7:                                        TATGTGGTCGAACTTGCAAGA21                                                        TyrValValGluLeuAlaArg                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO: 8:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 8:                                        TCAATGCCCCCAATTTGGGCCGAAGTGATGCGG33                                            SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 9:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 42                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 9:                                        CTGCGCCCAGATCAGGACTATCTGATGCACATCACGCACCGC42                                   LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 10:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 21                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 10:                                       TGGTCCCATGACGGCGCGAGG21                                                        TrpSerHisAspGlyAlaArg                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO: 11:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 1068                                                               (B) TYPE: Amino acid                                                           (C) STRANDEDNESS: Single                                                       (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: Peptide                                                    (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 11:                                       MetAlaGlyAsnGluTrpIleAsnGlyTyrLeuGluAlaIleLeu                                  151015                                                                         AspSerHisThrSerSerArgGlyAlaGlyGlyGlyGlyGlyGly                                  202530                                                                         GlyAspProArgSerProThrLysAlaAlaSerProArgGlyAla                                  354045                                                                         HisMetAsnPheAsnProSerHisTyrPheValGluGluValVal                                  505560                                                                         LysGlyValAspGluSerAspLeuHisArgThrTrpIleLysVal                                  657075                                                                         ValAlaThrArgAsnAlaArgGluArgSerThrArgLeuGluAsn                                  808590                                                                         MetCysTrpArgIleTrpHisLeuAlaArgLysLysLysGlnLeu                                  95100105                                                                       GluLeuGluGlyIleGlnArgIleSerAlaArgArgLysGluGln                                  110115120                                                                      GluGlnValArgArgGluAlaThrGluAspLeuAlaGluAspLeu                                  125130135                                                                      SerGluGlyGluLysGlyAspThrIleGlyGluLeuAlaProVal                                  140145150                                                                      GluThrThrLysLysLysPheGlnArgAsnPheSerAspLeuThr                                  155160165                                                                      ValTrpSerAspAspAsnLysGluLysLysLeuTyrIleValLeu                                  170175180                                                                      IleSerValHisGlyLeuValArgGlyGluAsnMetGluLeuGly                                  185190195                                                                      ArgAspSerAspThrGlyGlyGlnValLysTyrValValGluLeu                                  200205210                                                                      AlaArgAlaMetSerMetMetProGlyValTyrArgValAspLeu                                  215220225                                                                      PheThrArgGlnValSerSerProAspValAspTrpSerTyrGly                                  230235240                                                                      GluProThrGluMetLeuCysAlaGlySerAsnAspGlyGluGly                                  245250255                                                                      MetGlyGluSerGlyGlyAlaTyrIleValArgIleProCysGly                                  260265270                                                                      ProArgAspLysTyrLeuLysLysGluAlaLeuTrpProTyrLeu                                  275280285                                                                      GlnGluPheValAspGlyAlaLeuAlaHisIleLeuAsnMetSer                                  290295300                                                                      LysAlaLeuGlyGluGlnValGlyAsnGlyArgProValLeuPro                                  305310315                                                                      TyrValIleHisGlyHisTyrAlaAspAlaGlyAspValAlaAla                                  320325330                                                                      LeuLeuSerGlyAlaLeuAsnValProMetValLeuThrGlyHis                                  335340345                                                                      SerLeuGlyArgAsnLysLeuGluGlnLeuLeuLysGlnGlyArg                                  350355360                                                                      MetSerLysGluGluIleAspSerThrTyrLysIleMetArgArg                                  365370375                                                                      IleGluGlyGluGluLeuAlaLeuAspAlaSerGluLeuValIle                                  380385390                                                                      ThrSerThrArgGlnGluIleAspGluGlnTrpGlyLeuTyrAsp                                  395400405                                                                      GlyPheAspValLysLeuGluLysValLeuArgAlaArgAlaArg                                  410415420                                                                      ArgGlyValSerCysHisGlyArgTyrMetProArgMetValVal                                  425430435                                                                      IleProProGlyMetAspPheSerAsnValValValHisGluAsp                                  440445450                                                                      IleAspGlyAspGlyAspValLysAspAspIleValGlyLeuGlu                                  455460465                                                                      GlyAlaSerProLysSerMetProProIleTrpAlaGluValMet                                  470475480                                                                      ArgPheLeuThrAsnProHisLysProMetIleLeuAlaLeuSer                                  485490495                                                                      ArgProAspProLysLysAsnIleThrThrLeuValLysAlaPhe                                  500505510                                                                      GlyGluCysArgProLeuArgGluLeuAlaAsnLeuThrLeuIle                                  515520525                                                                      MetGlyAsnArgAspAspIleAspAspMetSerAlaGlyAsnAla                                  530535540                                                                      SerValLeuThrThrValLeuLysLeuIleAspLysTyrAspLeu                                  545550555                                                                      TyrGlySerValAlaPheProLysHisHisAsnGlnAlaAspVal                                  560565570                                                                      ProGluIleTyrArgLeuAlaAlaLysMetLysGlyValPheIle                                  575580585                                                                      AsnProAlaLeuValGluProPheGlyLeuThrLeuIleGluAla                                  590595600                                                                      AlaAlaHisGlyLeuProIleValAlaThrLysAsnGlyGlyPro                                  605610615                                                                      ValAspIleThrAsnAlaLeuAsnAsnGlyLeuLeuValAspPro                                  620625630                                                                      HisAspGlnAsnAlaIleAlaAspAlaLeuLeuLysLeuValAla                                  635640645                                                                      AspLysAsnLeuTrpGlnGluCysArgArgAsnGlyLeuArgAsn                                  650655660                                                                      IleHisLeuTyrSerTrpProGluHisCysArgThrTyrLeuThr                                  665670675                                                                      ArgValAlaGlyCysArgLeuArgAsnProArgTrpLeuLysAsp                                  680685690                                                                      ThrProAlaAspAlaGlyAlaAspGluGluGluPheLeuGluAsp                                  695700705                                                                      SerMetAspAlaGlnAspLeuSerLeuArgLeuSerIleAspGly                                  710715720                                                                      GluLysSerSerLeuAsnThrAsnAspProLeuTrpPheAspPro                                  725730735                                                                      GlnAspGlnValGlnLysIleMetAsnAsnIleLysGlnSerSer                                  740745750                                                                      AlaLeuProProSerMetSerSerValAlaAlaGluGlyThrGly                                  755760765                                                                      SerThrMetAsnLysTyrProLeuLeuArgArgArgArgArgLeu                                  770775780                                                                      PheValIleAlaValAspCysTyrGlnAspAspGlyArgAlaSer                                  785790795                                                                      LysLysMetLeuGlnValIleGlnGluValPheArgAlaValArg                                  800805810                                                                      SerAspSerGlnMetPheLysIleSerGlyPheThrLeuSerThr                                  815820825                                                                      AlaMetProLeuSerGluThrLeuGlnLeuLeuGlnLeuGlyLys                                  830835840                                                                      IleProAlaThrAspPheAspAlaLeuIleCysGlySerGlySer                                  845850855                                                                      GluValTyrTyrProGlyThrAlaAsnCysMetAspAlaGluGly                                  860865870                                                                      LysLeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                  875880885                                                                      TrpSerHisAspGlyAlaArgGlnThrIleAlaLysLeuMetGly                                  890895900                                                                      AlaGlnAspGlySerGlyAspAlaValGluGlnAspValAlaSer                                  905910915                                                                      SerAsnAlaHisCysValAlaPheLeuIleLysAspProGlnLys                                  920925930                                                                      ValLysThrValAspGluMetArgGluArgLeuArgMetArgGly                                  935940945                                                                      LeuArgCysHisIleMetTyrCysArgAsnSerThrArgLeuGln                                  950955960                                                                      ValValProLeuLeuAlaSerArgSerGlnAlaLeuArgTyrLeu                                  965970975                                                                      SerValArgTrpGlyValSerValGlyAsnMetTyrLeuIleThr                                  980985990                                                                      GlyGluHisGlyAspThrAspLeuGluGluMetLeuSerGlyLeu                                  99510001005                                                                    HisLysThrValIleValArgGlyValThrGluLysGlySerGlu                                  101010151020                                                                   AlaLeuValArgSerProGlySerTyrLysArgAspAspValVal                                  102510301035                                                                   ProSerGluThrProLeuAlaAlaTyrThrThrGlyGluLeuLys                                  104010451050                                                                   AlaAspGluIleMetArgAlaLeuLysGlnValSerLysThrSer                                  105510601065                                                                   SerGlyMet                                                                      (2) INFORMATION FOR SEQ ID NO: 12:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 3509                                                               (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 12:                                       GAATTCCGGCGTGGGCGCTGGGCTAGTGCTCCCGCAGCGAGCGATCTGAG50                           AGAACGGTAGAGTTCCGGCCGGGCGCGCGGGAGAGGAGGAGGGTCGGGCG100                          GGGAGGATCCG111                                                                 ATGGCCGGGAACGAGTGGATCAATGGGTACCTGGAGGCGATCCTC156                               MetAlaGlyAsnGluTrpIleAsnGlyTyrLeuGluAlaIleLeu                                  151015                                                                         GACAGCCACACCTCGTCGCGGGGTGCCGGCGGCGGCGGCGGCGGG201                               AspSerHisThrSerSerArgGlyAlaGlyGlyGlyGlyGlyGly                                  202530                                                                         GGGGACCCCAGGTCGCCGACGAAGGCGGCGAGCCCCCGCGGCGCG246                               GlyAspProArgSerProThrLysAlaAlaSerProArgGlyAla                                  354045                                                                         CACATGAACTTCAACCCCTCGCACTACTTCGTCGAGGAGGTGGTC291                               HisMetAsnPheAsnProSerHisTyrPheValGluGluValVal                                  505560                                                                         AAGGGCGTCGACGAGAGCGACCTCCACCGGACGTGGATCAAGGTC336                               LysGlyValAspGluSerAspLeuHisArgThrTrpIleLysVal                                  657075                                                                         GTCGCCACCCGCAACGCCCGCGAGCGCAGCACCAGGCTCGAGAAC381                               ValAlaThrArgAsnAlaArgGluArgSerThrArgLeuGluAsn                                  808590                                                                         ATGTGCTGGCGGATCTGGCACCTCGCGCGCAAGAAGAAGCAGCTG426                               MetCysTrpArgIleTrpHisLeuAlaArgLysLysLysGlnLeu                                  95100105                                                                       GAGCTGGAGGGCATCCAGAGAATCTCGGCAAGAAGGAAGGAACAG471                               GluLeuGluGlyIleGlnArgIleSerAlaArgArgLysGluGln                                  110115120                                                                      GAGCAGGTGCGTCGTGAGGCGACGGAGGACCTGGCCGAGGATCTG516                               GluGlnValArgArgGluAlaThrGluAspLeuAlaGluAspLeu                                  125130135                                                                      TCAGAAGGCGAGAAGGGAGACACCATCGGAGAGCTTGCGCCGGTT561                               SerGluGlyGluLysGlyAspThrIleGlyGluLeuAlaProVal                                  140145150                                                                      GAGACGACCAAGAAGAAGTTCCAGAGGAACTTCTCTGACCTTACC606                               GluThrThrLysLysLysPheGlnArgAsnPheSerAspLeuThr                                  155160165                                                                      GTCTGGTCTGACGACAATAAGGAGAAGAAGCTTTACATTGTGCTC651                               ValTrpSerAspAspAsnLysGluLysLysLeuTyrIleValLeu                                  170175180                                                                      ATCAGCGTGCATGGTCTTGTTCGTGGAGAAAACATGGAACTAGGT696                               IleSerValHisGlyLeuValArgGlyGluAsnMetGluLeuGly                                  185190195                                                                      CGTGATTCTGATACAGGTGGCCAGGTGAAATATGTGGTCGAACTT741                               ArgAspSerAspThrGlyGlyGlnValLysTyrValValGluLeu                                  200205210                                                                      GCAAGAGCGATGTCAATGATGCCTGGAGTGTACAGGGTGGACCTC786                               AlaArgAlaMetSerMetMetProGlyValTyrArgValAspLeu                                  215220225                                                                      TTCACTCGTCAAGTGTCATCTCCTGACGTGGACTGGAGCTACGGT831                               PheThrArgGlnValSerSerProAspValAspTrpSerTyrGly                                  230235240                                                                      GAGCCAACCGAGATGTTATGCGCCGGTTCCAATGATGGAGAGGGG876                               GluProThrGluMetLeuCysAlaGlySerAsnAspGlyGluGly                                  245250255                                                                      ATGGGTGAGAGTGGCGGAGCCTACATTGTGCGCATACCGTGTGGG921                               MetGlyGluSerGlyGlyAlaTyrIleValArgIleProCysGly                                  260265270                                                                      CCGCGGGATAAATACCTCAAGAAGGAAGCGTTGTGGCCTTACCTC966                               ProArgAspLysTyrLeuLysLysGluAlaLeuTrpProTyrLeu                                  275280285                                                                      CAAGAGTTTGTCGATGGAGCCCTTGCGCATATCCTGAACATGTCC1011                              GlnGluPheValAspGlyAlaLeuAlaHisIleLeuAsnMetSer                                  290295300                                                                      AAGGCTCTGGGAGAGCAGGTTGGAATTGGGAGGCCAGTACTGCCT1056                              LysAlaLeuGlyGluGlnValGlyAsnGlyArgProValLeuPro                                  305310315                                                                      TACGTGATACATGGGCACTATGCCGATGCTGGAGATGTTGCTGCT1101                              TyrValIleHisGlyHisTyrAlaAspAlaGlyAspValAlaAla                                  320325330                                                                      CTCCTTTCTGGTGCGCTGAATGTGCCAATGGTGCTCACTGGCCAC1146                              LeuLeuSerGlyAlaLeuAsnValProMetValLeuThrGlyHis                                  335340345                                                                      TCACTTGGGAGGAACAAGCTGGAACAACTGCTGAAGCAAGGGCGC1191                              SerLeuGlyArgAsnLysLeuGluGlnLeuLeuLysGlnGlyArg                                  350355360                                                                      ATGTCCAAGGAGGAGATCGATTCGACATACAAGATCATGAGGCGT1236                              MetSerLysGluGluIleAspSerThrTyrLysIleMetArgArg                                  365370375                                                                      ATCGAGGGTGAGGAGCTGGCCCTGGATGCGTCAGAGCTTGTAATC1281                              IleGluGlyGluGluLeuAlaLeuAspAlaSerGluLeuValIle                                  380385390                                                                      ACGAGCACAAGGCAGGAGATTGATGAGCAGTGGGGATTGTACGAT1326                              ThrSerThrArgGlnGluIleAspGluGlnTrpGlyLeuTyrAsp                                  395400405                                                                      GGATTTGATGTCAAGCTTGAGAAAGTGCTGAGGGCACGGGCGAGG1371                              GlyPheAspValLysLeuGluLysValLeuArgAlaArgAlaArg                                  410415420                                                                      CGCGGGGTTAGCTGCCATGGTCGTTACATGCCTAGGATGGTGGTG1416                              ArgGlyValSerCysHisGlyArgTyrMetProArgMetValVal                                  425430435                                                                      ATTCCTCCGGGAATGGATTTCAGCAATGTTGTAGTTCATGAAGAC1461                              IleProProGlyMetAspPheSerAsnValValValHisGluAsp                                  440445450                                                                      ATTGATGGGGATGGTGACGTCAAAGATGATATCGTTGGTTTGGAG1506                              IleAspGlyAspGlyAspValLysAspAspIleValGlyLeuGlu                                  455460465                                                                      GGTGCCTCACCCAAGTCAATGCCCCCAATTTGGGCCGAAGTGATG1551                              GlyAlaSerProLysSerMetProProIleTrpAlaGluValMet                                  470475480                                                                      CGGTTCCTGACCAACCCTCACAAGCCGATGATCCTGGCGTTATCA1596                              ArgPheLeuThrAsnProHisLysProMetIleLeuAlaLeuSer                                  485490495                                                                      AGACCAGACCCGAAGAAGAACATCACTACCCTCGTCAAAGCGTTT1641                              ArgProAspProLysLysAsnIleThrThrLeuValLysAlaPhe                                  500505510                                                                      GGAGAGTGTCGTCCACTCAGGGAACTTGCAAACCTTACTCTGATC1686                              GlyGluCysArgProLeuArgGluLeuAlaAsnLeuThrLeuIle                                  515520525                                                                      ATGGGTAACAGAGATGACATCGACGACATGTCTGCTGGCAATGCC1731                              MetGlyAsnArgAspAspIleAspAspMetSerAlaGlyAsnAla                                  530535540                                                                      AGTGTCCTCACCACAGTTCTGAAGCTGATTGACAAGTATGATCTG1776                              SerValLeuThrThrValLeuLysLeuIleAspLysTyrAspLeu                                  545550555                                                                      TACGGAAGCGTGGCGTTCCCTAAGCATCACAATCAGGCTGACGTC1821                              TyrGlySerValAlaPheProLysHisHisAsnGlnAlaAspVal                                  560565570                                                                      CCGGAGATCTATCGCCTCGCGGCCAAAATGAAGGGCGTCTTCATC1866                              ProGluIleTyrArgLeuAlaAlaLysMetLysGlyValPheIle                                  575580585                                                                      AACCCTGCTCTCGTTGAGCCGTTTGGTCTCACCCTGATCGAGGCT1911                              AsnProAlaLeuValGluProPheGlyLeuThrLeuIleGluAla                                  590595600                                                                      GCGGCACACGGACTCCCGATAGTCGCTACCAAGAATGGTGGTCCG1956                              AlaAlaHisGlyLeuProIleValAlaThrLysAsnGlyGlyPro                                  605610615                                                                      GACATTACAAATGCATTAAACAACGGACTGCTCGTTGACCCACAC2001                              ValAspIleThrAsnAlaLeuAsnAsnGlyLeuLeuValAspPro                                  620625630                                                                      GTCGACCAGAACGCCATCGCTGATGCACTGCTGAAGCTTGTGGCA2046                              HisAspGlnAsnAlaIleAlaAspAlaLeuLeuLysLeuValAla                                  635640645                                                                      GACAAGAACCTGTGGCAGGAATGCCGGAGAAACGGGCTGCGCAAC2091                              AspLysAsnLeuTrpGlnGluCysArgArgAsnGlyLeuArgAsn                                  650655660                                                                      ATCCACCTCTACTCATGGCCGGAGCACTGCCGCACTTACCTCACC2136                              IleHisLeuTyrSerTrpProGluHisCysArgThrTyrLeuThr                                  665670675                                                                      AGGGTGGCCGGGTGCCGGTTAAGGAACCCGAGGTGGCTGAAGGAC2181                              ArgValAlaGlyCysArgLeuArgAsnProArgTrpLeuLysAsp                                  680685690                                                                      ACACCAGCAGATGCCGGAGCCGATGAGGAGGAGTTCCTGGAGGAT2226                              ThrProAlaAspAlaGlyAlaAspGluGluGluPheLeuGluAsp                                  695700705                                                                      TCCATGGACGCTCAGGACCTGTCACTCCGTCTGTCCATCGACGGT2271                              SerMetAspAlaGlnAspLeuSerLeuArgLeuSerIleAspGly                                  710715720                                                                      GAGAAGAGCTCGCTGAACACTAACGATCCACTGTGGTTCGACCCC2316                              GluLysSerSerLeuAsnThrAsnAspProLeuTrpPheAspPro                                  725730735                                                                      CAGGATCAAGTGCAGAAGATCATGAACAACATCAAGCAGTCGTCA2361                              GlnAspGlnValGlnLysIleMetAsnAsnIleLysGlnSerSer                                  740745750                                                                      GCGCTTCCTCCGTCCATGTCCTCAGTCGCAGCCGAGGGCACAGGC2406                              AlaLeuProProSerMetSerSerValAlaAlaGluGlyThrGly                                  755760765                                                                      AGCACCATGAACAAATACCCACTCCTGCGCCGGCGCCGGCGCTTG2451                              SerThrMetAsnLysTyrProLeuLeuArgArgArgArgArgLeu                                  770775780                                                                      TTCGTCATAGCTGTGGACTGCTACCAGGACGATGGCCGTGCTASC2496                              PheValIleAlaValAspCysTyrGlnAspAspGlyArgAlaSer                                  785790795                                                                      AAGAAGATGCTGCAGGTGATCCAGGAAGTTTTCAGAGCAGTCCGA2541                              LysLysMetLeuGlnValIleGlnGluValPheArgAlaValArg                                  800805810                                                                      GACTCCCAGATGTTCAAGATCTCAGGGTTCACGCTGTCGACTGCC2586                              SerAspSerGlnMetPheLysIleSerGlyPheThrLeuSerThr                                  815820825                                                                      TCGATGCCGTTGTCCGAGACACTCCAGCTTCTGCAGCTCGGCAAG2631                              AlaMetProLeuSerGluThrLeuGlnLeuLeuGlnLeuGlyLys                                  830835840                                                                      ATCCCAGCGACCGACTTCGACGCCCTCATCTGTGGCAGCGGCAGC2676                              IleProAlaThrAspPheAspAlaLeuIleCysGlySerGlySer                                  845850855                                                                      GAGGTGTACTATCCTGGCACGGCGAACTGCATGGACGCTGAAGGA2721                              GluValTyrTyrProGlyThrAlaAsnCysMetAspAlaGluGly                                  860865870                                                                      AAGCTGCGCCCAGATCAGGACTATCTGATGCACATCAGCCACCGC2766                              LysLeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                  875880885                                                                      TGGTCCCATGACGGCGCGAGGCAGACCATAGCGAAGCTCATGGGC2811                              TrpSerHisAspGlyAlaArgGlnThrIleAlaLysLeuMetGly                                  890895900                                                                      GCTCAGGACGGTTCAGGCGACGCTGTCGAGCAGGACGTGGCGTCC2856                              AlaGlnAspGlySerGlyAspAlaValGluGlnAspValAlaSer                                  905910915                                                                      AGTAATGCACACTGTGTCGCGTTCCTCATCAAAGACCCCCAAAAG2901                              SerAsnAlaHisCysValAlaPheLeuIleLysAspProGlnLys                                  920925930                                                                      GTGAAAACGGTCGATGAGATGAGGGAGCGGCTGAGGATGCGTGGT2946                              ValLysThrValAspGluMetArgGluArgLeuArgMetArgGly                                  935940945                                                                      CTCCGCTGCCACATCATGTACTGCAGGAACTCGACAAGGCTTCAG2991                              LeuArgCysHisIleMetTyrCysArgAsnSerThrArgLeuGln                                  950955960                                                                      GTTGTCCCTCTGCTAGCATCAAGGTCACAGGCACTCAGGTATCTT3036                              ValValProLeuLeuAlaSerArgSerGlnAlaLeuArgTyrLeu                                  965970975                                                                      TCCGTGCGCTGGGGCGTATCTGTGGGGAACATGTATCTGATCACC3081                              SerValArgTrpGlyValSerValGlyAsnMetTyrLeuIleThr                                  980985990                                                                      GGGGAACATGGCGACACCGATCTAGAGGAGATGCTATCCGGGCTA3126                              GlyGluHisGlyAspThrAspLeuGluGluMetLeuSerGlyLeu                                  99510001005                                                                    CACACCGTGATCGTCCGTGGCGTCACCGAGAAGGGTTCGGAAGCA3171                              HisLysThrValIleValArgGlyValThrGluLysGlySerGlu                                  101010151020                                                                   CTGAAGGTGAGGAGCCCAGGAAGCTACAAGAGGGACGATGTCGTC3216                              AlaLeuValArgSerProGlySerTyrLysArgAspAspValVal                                  102510301035                                                                   CCGTCTGAGACCCCCTTGGCTGCGTACACGACTGGTGAGCTGAAG3261                              ProSerGluThrProLeuAlaAlaTyrThrThrGlyGluLeuLys                                  104010451050                                                                   GCCGACGAGATCATGCGGGCTCTGAAGCAAGTCTCCAAGACTTCC3306                              AlaAspGluIleMetArgAlaLeuLysGlnValSerLysThrSer                                  105510601065                                                                   AGCGGCATG3315                                                                  SerGlyMet                                                                      TGAATTTGATGCTTCTTTTACATTTTGTCCTTTTCTTCACTGCTATATAA3365                         AATAAGTTGTGAACAGTACCGCGGGTGTGTATATATATATTGCAGTGACA3415                         AATAAAACAGGACACTGCTAACTATACTGGTGAATATACGACTGTCAAGA3465                         TTGTATGCTAAGTACTCCATTTCTCAATGTATCAATCGGAATTC3509                               (2) INFORMATION FOR SEQ ID NO: 13:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 13:                                       TCAATGCCACCAATATGGGCAGAAGTAATGCGA33                                            SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 14:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 14:                                       AGCATGCCCCCCATCTGGGCCGAGGTCATGAGC33                                            SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 15:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 15:                                       TCGATGCCGCCGATTTGGGCGGAAGTGATGCGG33                                            SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 16:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 16:                                       TCTATGCCTCCTATATGGGCTGAAGTTATGCGT33                                            SerMetProProIleTrpAlaGluValMetArg                                              1510                                                                           (2) INFORMATION FOR SEQ ID NO: 17:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 42                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 17:                                       TTAAGACCAGACCAAGACTACTTAATGCACATAAGACACAGA42                                   LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 18:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 42                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 18:                                       CTGCGCCCCGATCAGGATTATCTGATGCATATCTCCCATCGC42                                   LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 19:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 42                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 19:                                       TTCAGGCCGGACCAAGACTACTTGATGCACATTAGGCACAGG42                                   LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 20:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 42                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 20:                                       TTTAGTCCTGACCAAGACTACTTTATGCACATAAGTCACAGT42                                   LeuArgProAspGlnAspTyrLeuMetHisIleSerHisArg                                     1510                                                                           (2) INFORMATION FOR SEQ ID NO: 21:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 6, 9 and 18                          indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 21:                                       ATGCCNCCNATATGGGCNGA20                                                         (2) INFORMATION FOR SEQ ID NO: 22:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 22:                                       ATGCCCCCCATCTGGGCCGA20                                                         (2) INFORMATION FOR SEQ ID NO: 23:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 6, 9 and 18                          indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 23:                                       ATGCCNCCNATTTGGGCNGA20                                                         (2) INFORMATION FOR SEQ ID NO: 24:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in position 15                                    indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 24:                                       CTAGTCCTAATAGANTACGT20                                                         (2) INFORMATION FOR SEQ ID NO: 25:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in position 15                                    indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 25:                                       CTGGTTCTGATGGANTACGT20                                                         (2) INFORMATION FOR SEQ ID NO: 26:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 6, 9                                 and 18 indicates inosine                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 26:                                       TACGGNGGNTAAACCCGNCT20                                                         (2) INFORMATION FOR SEQ ID NO: 27:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 27:                                       TACGGCGGCTAGACCCGCCT20                                                         (2) INFORMATION FOR SEQ ID NO: 28:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 6 and 9                              indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 28:                                       TACGGNGGNTATACCCGCCT20                                                         (2) INFORMATION FOR SEQ ID NO: 29:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in position 15                                    indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 29:                                       GACCAAGACTACCTNATGCA20                                                         (2) INFORMATION FOR SEQ ID NO: 30:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 20                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 30:                                       GATCAGGATTATCTCATGCA20                                                         (2) INFORMATION FOR SEQ ID NO: 31:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 6 and 12                             indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 31:                                       ACCCGNCTCCANTACGC17                                                            (2) INFORMATION FOR SEQ ID NO: 32:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in position 6                                     indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 32:                                       ACCCGNCCTCACTACTC17                                                            (2) INFORMATION FOR SEQ ID NO: 33:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 33:                                       TACGTATAATCAGTAGC17                                                            (2) INFORMATION FOR SEQ ID NO: 34:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 34:                                       TACGTGTAGTCGGTGTC17                                                            (2) INFORMATION FOR SEQ ID NO: 35:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 17                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 35:                                       TACGTATATTCAGTAGC17                                                            (2) INFORMATION FOR SEQ ID NO: 36:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (ix) FEATURE:                                                                  (D) OTHER INFORMATION: The N in positions 3, 6 and 9                           indicates inosine                                                              (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 36:                                       AANGCNGGNCTAGT14                                                               (2) INFORMATION FOR SEQ ID NO: 37:                                             (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 14                                                                 (B) TYPE: Nucleic acid                                                         (C) STRANDEDNESS: Unknown                                                      (D) TOPOLOGY: Unknown                                                          (ii) MOLECULE TYPE: cDNA                                                       (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 37:                                       GACTCCGGCCTGGT14                                                               __________________________________________________________________________ 

We claim:
 1. An isolated maize protein consisting of saccharose phosphate synthetase having the amino acid sequence of FIG.
 7. 2. An isolated protein from maize consisting of saccharose phosphate synthetase having a molecular weight of 110 to 130 dK and having at least one peptide with the following amino acid sequence selected from the group consisting ofThv Trp Ile Lys, Try Val Val Glu Leu Ala Arg, Ser Met Pro Pro Ile Trp Ala Glu Val Met Arg, Leu Arg Pro Asp Gln Asp Try Leu Met His Ile Ser His Arg and Trp Ser His Asp Gly Ala Arg. 